This invention relates to an apparatus for changing tuyeres on a blast furnace. More particularly it relates to apparatus for handling the tuyeres and their associated tuyere stock assemblies during installation in and removal from a blast furnace.
As is well known in the art, a blast furnace is one of the largest single installations in any fully integrated steel mill which is designed to produce pig iron essential for the manufacture of steel. In the production of iron, a predetermined quantity of iron ore, iron pellets, sinter, coke and limestone is charged into the furnace and is ignited. Effective and controlled combustion is sustained by blowing preheated air at temperatures some 2000.degree.-2300.degree. F. through the furnace. The hot air is blown into a circular refractory lined pipe known as the bustle pipe and from there enters a series of blow-pipes and water cooled copper nozzles distributed uniformly around the circumference of the furnace. These copper nozzles are known as tuyeres. The tuyeres are in direct contact with the molten iron and are subject to extreme heat, abrasion etc., and thus must be replaced from time to time. It is necessary to remove the lower tuyere stock and blow-pipe assembly to change the tuyere. A modern large size blast furnace may have as many as forty blow-pipe assemblies and tuyeres and the weight of an individual tuyere stock and blow-pipe may reach 3000 lbs.
The problem of changing blow-pipes and tuyeres is compounded by the sizes and weights of the components involved as well as by the intense heat, the proximity of cooling pipes, furnace supporting columns and structures and the furnace tapping arrangements.
On smaller furnaces of an older design having some 12 to 16 tuyeres, the tuyere changes are normally performed by the furnace crew with the aid of relatively simple lifting devices. On newer relativey large furnaces, much more complex rigging is involved and a crew of highly trained specialists is required to accomplish the tuyere replacements. A fork-lift truck is also needed to handle the tuyere stock and blow-pipe assembly to remove a tuyere. The whole operation is considered time consuming, dangerous and difficult. Several types of apparatus have been devised in the part in an attempt to facilitate the tuyere changing operation. However, to the best of applicants' knowledge, these techniques and equipment were never used with any degree of success and generally did not find acceptance by the steel making industry.